The after-treatment of exhaust gas of internal combustion engines is commonly constructed of passive systems, which in all operational situations are entirely flown through by the exhaust gas. When flowing through the system, the exhaust gas experiences some resistance, which reduces the overall efficiency of the system. For reducing emissions and exhaust gas noise in common operational situations of low load, it would be desirable to have available switchable systems in which parts of the exhaust gas apparatus are closed or decoupled by control members, and only partial regions are used.
For example, it is known from international application WO 2010/034450 A1 (in particular FIGS. 1 to 3 thereof) to recirculate part of the exhaust gas stream into the internal combustion engine via a recirculation duct by means of an exhaust gas valve.
If an exhaust gas main pipe is to be closed for the full exhaust gas volume stream, and the exhaust gas stream is to be diverted via separate member upstream of the closure, and is to be reintroduced via a further member downstream of the closure, several of the known valves have to foe employed and coordinated in the system, resulting in an according space requirement and effort for the actuating and addressing.
Furthermore, it is known to charge a latent heat reservoir with the engine heat of a vehicle, and to release the energy stored in the latent heat reservoir at cold starting.